19 February 2024

For over 10 years, local volunteers organised by the Tansy Beetle Action Group (or TBAG for short) have been pacing the banks of the River Ouse, counting beetles one by one on clumps of  Tansy – its foodplant.

2023 proved to be a record year for the Endangered Tansy Beetle (Chrysolina graminis) in its heartland along the River Ouse. The annual survey, carried out by volunteers, revealed a population estimate of 91,000 – nearly double the previous highest estimate of 46,000 back in 2016.  Nobody could have predicted the surge in numbers of this striking iridescent green leaf beetle in 2023 – with one lucky volunteer counting more than 20,000 beetles!

Conservationists have welcomed the positive news and say it demonstrates the success of changes to the riverbank’s management. Working together with local landowners they have made sure that its essential Tansy foodplant is left growing to help the beetles complete their lifecycle. However, despite the record numbers, there are still concerns about how the Tansy Beetle might cope with the increase in summer flooding events that are expected with climate change; as well as the threat of Tansy being outcompeted by invasive plants, such as Himalayan Balsam.

Vicky Wilkins, Programmes Manager at the Species Recovery Trust says, “It’s wonderful news to hear how well our Tansy Beetles have fared in 2023 – in fact their numbers have grown seven times in just one year! But it is only through the hard work of dedicated local volunteers over many years that we have been able to see the difference that better riverbank management has made. There is still a lot more to do to secure the future of this stunning beetle.

Karim Vahed, England Manager at Buglife, says, “Against the backdrop of widespread insect declines, it is very welcomed for there to be a success story. The improved fortunes of the Tansy Beetle show just how careful we need to be in caring for nature – Tansy is their main food plant on the River Ouse, and if a clump is cut, the beetles have to walk to find the next patch as they are poor fliers. So all of the work in York to maintain its precious food plants are paying off.”

The Tansy Beetle has been hailed for its beauty as far back as the Victorians who used their shiny wing cases as sequins.  In recent years the beetle has been the subject of a York mural, by street artist ATM, and has inspired countless other artistic endeavours.

Once widespread in Britain, the Tansy Beetle is currently Endangered in the UK, it is now only found along the banks of a 45km stretch of the River Ouse around York, with much smaller populations in East Anglia.

Conservation of this threatened species is steered by the Tansy Beetle Action Group, a collaboration of local and national organisations seeking to save the species and support more resilient habitat.

If you would like to learn more about these vibrant bejewelled beetles of York please visit the Species Recovery Trust and Buglife websites.  We are looking for businesses to sponsor Tansy beetle conservation work, if you are interested please contact info@speciesrecoverytrust.org.uk